Home / Blog / How to Effectively Conduct a Legacy System Integration

How to Effectively Conduct a Legacy System Integration

More and more companies face the unsatisfying reality of dealing with legacy systems and conclude that they should make a change. However, a significant portion of such systems supports daily business operations, making it difficult to rip and replace them entirely. 

Did you know that nearly 97% of all collected data ends up being just stored away and never gets a chance to be used again? On top of that, a big part of this data is outdated and redundant, delivering little to no value to the company. But you can change that by reactivating your legacy software. 

Luckily, you don’t need to disrupt the whole IT environment to get a new technology platform. After having invested money and time into your legacy application, a complete overthrow of the entire system seems like a waste, right? There is a way of adopting newer technologies without starting from scratch. Instead of building a brand new application, you can upgrade your old one by implementing a method called legacy systems integration. 

But what is legacy system integration, and is it relevant for your business? 

What Is Legacy Systems Integration?

Legacy system integration deals with connecting APIs on-premises and in the cloud. In other words, it transports data from on-premises legacy systems and advancing new systems that drive the business further. The main challenge is to detect an outdated system and ensure communication between it and the cloud applications. Legacy system integration is also necessary for untangling the so-called spaghetti code when integrating a company’s internal systems. 

When Is Legacy System Integration Relevant?

How can you tell if you have a legacy system on your hands and whether it needs modernization? What are the main reasons to integrate legacy systems? There are eight of them: 

  • Shorter time-to-market

44% of organizations that offer financial services state that integrating new technology is one of the biggest pain points. Integration of a new solution into the existing environment becomes a hardship on the way to digital transformation. Luckily, legacy system integration helps you build a lightweight product that will present a competitive advantage. On top of that, this process speeds up time-to-market and allows you to deploy more frequently. 

  • Increased performance

Newer technologies come with better performance as well as more reliable and smooth processes. Additionally, modernized solutions reduce security risks and facilitate better functionality. 

  • Access to buried data

As mentioned before, 97% of data gets lost and forgotten in legacy systems. You can improve your business processes by unlocking the value of data and utilizing it. 

Data silos in legacy systems | ModLogix
  • Improved agility

By adjusting your IT environment to fit into the agile and cutting-edge present, you leave a bigger window for future changes.  

  • Easier to follow data compliance standards

Some industries, such as healthcare, require a specific process of data transfer. Outdated legacy software cannot ensure this strict flow and hinder changes. 

  • Smoother integration with third-party tools

Newer systems like CRMs, accounting software, and other third-party tools open up new opportunities for your business. However, to capture the benefits of modern systems, you need to bridge the gap between the legacy software and the new system. 

  • Eliminate financial inefficiencies 

Every IT business strives to be modern and up-to-date, which is hard to achieve when you keep using outdated software. Jumping on the innovation train will improve your company image and might even attract investors. 

  • A valid alternative to legacy system replacement

Integration is far less invasive and expensive than a complete replacement of a system. Unlike smooth and continuous integration, the latter requires bigger investments, resources, and time.

Legacy System Integration with EMR Case Study

Legacy System Integration with EMR Case Study

3 Types of Integration of Legacy Systems

There is more than one approach to the integration of legacy systems, but we’ll focus on the three basic ones and the one ready-to-go. 

Service layers

Adding service layers is a common strategy when it comes to legacy systems modernization. They act as a mediator between your outdated application and a new system. Service layers transform the data before it hits the new or existing system. 

Data access layers (DALs)

Data access layers act as a database that allows developers to use various data stored and access information easier. They also facilitate a separate modification of logical data that won’t affect the business layer. This is a beneficial trait for any system, including modern ones, especially when a need to extend comes up. Using DALs, you’ll be able to replicate a data solution that will allow you to deploy a business or data intelligence or artificial solution. 

Application Program Interfaces (APIs)

As one of the most common legacy system integration models, APIs unmask functions of your legacy software to outside integration and make the process significantly simpler. APIs provide the much-needed flexibility and ensure better performance. 

Basic types of integration of legacy systems | ModLogix

Ready solution for legacy systems integration

Instead of executing the cumbersome process of integration by yourself, you can purchase a ready-made solution. Some companies offer a simple solution for seamless integration, thus solving the problems with legacy infrastructure. Although it is a more cost-effective option, there is a catch. Ready solutions usually pose a greater risk of sensitive data loss. You will be better off choosing a vendor who will develop a custom solution for your business and control every step of the process.

Which Legacy System Integration Issues You Might Face and How to Solve Them

  • Lack of necessary documentation

Modernization of legacy systems is not an easy task and requires constant maintenance and expansion. Furthermore, legacy systems require a lot of patching. Most of the time, companies face a lack of comprehensive documentation to the system architecture as well as system changes and patches, which makes the process longer and more challenging. 


Although you cannot uncover the lack of documentation of legacy code, the best way to avoid these mistakes is to develop a set of standards and processes for the future.

  • Monolithic systems

Monolithic systems pose a big challenge to legacy system integrators. The way they are built does not allow to separate their functional aspects like error handling, user interface, and data processing. Monolithic architecture implies that the components are blended and not architecturally separate, making integration significantly more difficult. 


Here you should conduct an architecture audit to determine whether you want to keep some parts of the old system and assess how new parts will interact with old ones to prevent disruption. 

  • Talent Gap

The talent gap derives from the lack of programmers that can write code using legacy programming languages. According to research made by Veeam, 44% of companies state they cannot proceed with modernization plans due to a lack of necessary IT skills on the market.


If the situation occurs when the technologies are so outdated that you cannot find anyone to command them, you would need to rewrite separate components using new tech stack in the process of modernization. 

  • Security Risks

One of the biggest issues of working with legacy software is their vulnerability and risk of exposure to security threats. The integration process itself is also prone to security risks due to the transfer of sensitive data between on-premises and cloud solutions and the non-availability of software patches. 


The right vendor will help you assess the risk exposure and avoid or at least mitigate these issues. If you are unclear with the process of vendor screening, read our explicit guide on how to validate legacy vendors

Integration as a service is the most common way to facilitate real-time exchange of data between legacy/modern systems and avoid being trapped in outdated technology.

Our Experience 

ModLogix is an IT company that has been on the market since 2014. Our mission is to revive legacy applications and help businesses grow and expand in the right direction. We guarantee an increase in performance, easier development, and enhanced user experience.

During our career, we have helped many companies to innovate and upgrade their applications.

One of our proudest cases

  • Client’s Issue

Our client has a system that helps healthcare facilities to analyze patient’s coverage and avoid billing errors. After having faced an increased number of customers, the client decided to optimize their patient verification process. To achieve their goals, our client needed a solution that would accelerate data exchange. 

  • Technologies and Tools Used

.NET Framework 4.5, RabbitMQ, MassTransit

Principles: SOLID, KISS, DRY.

  • The Outcome

We’ve created a microservices-based architecture with message queues to organize the data transfer from multiple services. It also enabled achieving a stable load balance of the system. Additionally, we managed to build a web scraper to extract data from EMR platforms and a wrapper for our client to accept files.  

Read the full case study about legacy systems integration.

  • The Results in Numbers:
  1. The speed of report generation has increased by 12.3 times
  2. The customer base grew 43%
  3. Our client can handle 15,000 proceeded requests per day

Contact our team of experts, and you’ll receive a unique approach to legacy integration and benefits from our first-hand expertise of the best modernization providers. 

Final Thoughts

Uncoordinated and unplanned adoption of new solutions and technologies leads to highly complex IT ecosystems that urgently need to be upgraded. Without focusing on integration, companies end up with multiple hardware systems, IaaS, and shadow applications that do not fit into the ecosystem. This is why it’s vital to correctly assess your outdated systems and establish a need for a change. To achieve your goals and avoid unwanted consequences that might make your initial system updating plan undeliverable, you should refer to professionals. Their expertise will guarantee a detailed plan for legacy system integration and bring you closer to success. 

Latest Blog Posts

Ask Us Any Question

* Please enter your name
* Please leave a message

    How to protect your business from getting obsolete?

    Download the white paper to discover hands-on approaches to aging software and mainframes.

    Get Your FREE Template!

    Please, provide the email address so that we can send the whitepaper to you.

    * Please enter your name

      We use cookies to ensure that we give you the best experience on our website. By continuing to browse this site you accept the use of cookies.

      Get Your FREE Template!

      Please, provide the email address so that we can send the whitepaper to you.

      * Please enter your name

        Get Your FREE Template!

        Please, provide the email address so that we can send the checklist to you.

        * Please enter your name